Treatment of crude petroleum during its transfer from the production site to the storage location is of capital importance since the products injected make it possible to obtain an oil which complies with commercial specifications.
The detection of a stoppage of injection and the teletransmission thereof will make it possible to avoid expensive incidents such as might immobilise storage or reveal loads which are not in accordance with specifications.
The product is generally injected by means of an alternating or reciprocating pump driven by a motor supplied with gas or electricity. Faults in injection emanate either from a stoppage of the supply of gas or electricity or from a lack of product to be injected.
Flow monitors are known which are installed in a sleeve so that they can be mounted in a pipeline. A valve oscillating in the pipeline indicates the excess or lack of flow. However, these devices are designed to monitor considerable flow levels at pressures which are not very high and they are not suitable for clearly and manifestly detecting any absence of flow and do not therefore constitute a solution to the problem posed.
Flow meters are known which have a float and which comprise a vertical measuring cone of upwardly increasing cross-section and inside which there is a float. When fluid is flowing from the bottom upwards through the cone of measurement, the float rises and assumes such a position that the ascending force due to the flow balances the weight of the float. A level of flow through this instrument corresponds to every position of the float. If the tube is transparent, graduations are marked on the tube and make it possible directly to read the rate of flow. If the tube is opaque, a magnetic bar is placed in the float and a detector is provided to read any modification in magnetic field, translating these indications into a dial reading by means of a movable needle.
Float-type flow meters are fragile and are rather more laboratory instruments rather than work site equipment.